For anyone who has bitcoin and is interested in donating a small portion to a charity, here's one: projectminivan.com .

This woman needs a wheelchair van because her rotator cuff has been destroyed from taking apart her current wheelchair and putting it in her car every time.  (The video has some footage of this.)  If she could roll into a van and just drive away, that'd really be a huge improvement in her life.

I think primecoin is maybe the best concept out there.

Once upon a time, gold was thought to be a great indicator of an economy, because the supplies were supposed to be infinite, while increases in the technological prowess of an economy would be reflected in its ability to mine gold.  e.g. Gold production would keep up with the rest of the goods and services produced in an economy.

Primecoin is close to this, if we think that excess computing capacity is a good indication of a networked technological economy, primecoin becomes more difficult in terms of the original hardware used to mine it, but should keep step with the economy as a whole, if computing capacity is an indication.  So I think it's pretty interesting.